BS.Player can't reproduce high or improved quality videos from YouTube.
For example, if I put this URL, player will play (only) normal quality of video:
http://www.youtube.com/watch?v=OVL5Mfgw7Pw
And when I put URL of improved video:
http://www.youtube.com/watch?v=CQzUsTFqtW0&fmt=18
I get normal video quality:
http://www.youtube.com/watch?v=CQzUsTFqtW0
It's a good idea to include BS.P features to switch between different vesions of YouTube streaming videos.
:)